Dental amalgam continues to be used for over 75 percent of all single tooth restorations. Failures related to the material are frequent. Recent reports of research indicate the potential for eliminating the gamma 2 phase (weakest and most corrosive). However, the dispersion system also lowers the tensile strength and the gold added alloy is much more expensive. Other metallic elements may be used to form stable tin compounds. The proper combination of additional alloys to retain or improve current physical properties at the present cost is one goal. To establish more realistic values to physical properties required by ADA Specification #1, such as dimensional change during hardening, is another goal. Also to modify handling techniques to provide a first-sitting finish that eliminates the need for subsequent polishing is a goal. Each experimental amalgam will be completely characterized in the laboratory and clinical restorations will be placed and observed for six years. Evaluation of various observations of the restorations will be correlated with the laboratory characterizations to sort out factors contributing to strengths and weaknesses. The project will also include training for a dental student in dental materials research.